Disclosed are a metal aluminum nano-adjuvant, a vaccine composition and a preparation method therefor and a use thereof. The vaccine adjuvant comprises metal aluminum nanoparticles, and can be used as a candidate adjuvant for preventive vaccines and therapeutic vaccines for various diseases such as infections, autoimmune diseases and tumors. The combined use of the vaccine adjuvant provided by the present disclosure and antigen can effectively enhance the humoral immune response and the cellular immune response of the vaccine, and the enhancement effect is significantly better than that of the commercially available aluminum hydroxide adjuvant.